1. Field of the Invention
The present invention relates to footwear. More specifically, the present invention relates to methods and apparatus for a sandal having an active self-adjusting harness which cooperates with a center toe strap and an independent adjustable heel strap to provide for continuous adjustment for securely affixing the sandal to a human foot during physical activity.
2. Description of the Prior Art
The prior art is directed to methods and apparatus for sandal type footwear used during physical activities. Sandals are one of the first types of footwear known to mankind and continue to be popular. Early sandals included a flat component formed of a suitable material such as leather that served as a sole. The flat sole was placed under the foot to provide protection against the ground surface. Various methods to attach the sandal to the foot are also known. Some attachment examples include the use of a suitable material such as leather to attach the sole of the sandal to the toes or ankle of the foot.
In more recent times, a vamp which covers the instep of the foot was employed to provide a slide type sandal. The vamp only partially covered the top of the foot so that the toes might extend outward into the open air. In the alternative, the vamp may cover most of the top of the foot or even enclose the entire forward portion of the foot. Leather laces could be employed to improve the attachment of the slide type sandal to the foot by lashing the sole and/or the vamp of the sandal to the foot. However, neither of these types of means for attaching the sandal to the foot were satisfactory during rigorous physical activity.
The rear heel strap was subsequently introduced which was attached to the vamp or other structural component of the sandal. The rear heel strap was used to wrap around the heel of the foot to ensure that the sandal remained attached to the foot. Sandals often incorporated buckles, hook and eyelet fasteners and other types of mechanical fasteners to adjust the tension in the rear heel strap. The greater the tension in the rear heel strap, the tighter the sandal was attached to the foot. This feature was an improvement in securing the sandal to the foot during leisure activities. However, the rear heel strap often became loose during rigorous activities such as competing in baseball, beach ball sports and running in the sand to name a few. Under these conditions, the rear heel strap would slip down around the heel of the foot resulting in the sandal falling off of the foot.
Thus, sandals were subsequently modified to improve the attachment mechanism to the human foot for use during physical activity. In a first example, a sandal is known having an elongated sole configured to the profile of a human footprint. The sandal has a toe end and a heel end and employs a toe strap connected at two anchor points to grip the forward part of the wearer's foot. A heel strap is connected at two anchor points to grip the ankle of the wearer's foot. A lateral strap is connected between the toe strap and the heel strap which is located on the outside of the sole and parallel to its surface so that it is operable to stabilize the other straps and to maintain essentially constant tension in the individual straps as the sole flexes. The toe and heel straps are infinitely adjustable so that the wearer can cinch the sandal to his foot by adjusting the straps in a manner that the sandal will not be dislodged during rigorous activity.
In another example, a sandal construction includes a convertible heel harness which is employed to minimize foot slippage in its closed rearward position. Likewise, the convertible heel harness becomes a part of a frontal ankle strap in its alternate, forward position. The sandal may be slipped into and worn with an open back, or may be placed upon the foot with the harness engaging the heel.
Thus, there is a need in the art for a sandal intended for use during rigorous physical activity that includes an insole and an active, self-adjusting harness connected thereto wherein the harness is comprised of a single continuous strap having a plurality of strap sections. The self-adjusting harness in combination with a center toe strap and an independent adjustable heel strap functions to retain the sandal securely to a human foot. The harness is active in nature in that it is continuously self-adjusting and requires only a single over-the-instep strap closure to attach the sandal to the foot. The greater the upward pressure applied on the sandal, the tighter the harness becomes about the foot.